Depends on how the MG conversion was registered. MGs are not rifles, therefore min length does not apply. If the receiver was registered, then the MG reg would apply and no SBR exists. OTOH, if the trigger pack or sear were the registered item, the pack could be removed from the rifle, leaving an SBR. 2 stamps. However, one can "marry" a trigger pack and a rifle together (can't use the pack in a different rifle, so noted in ATF records) and then the combo is considered the MG (one stamp). You can later "divorce" the trigger pack for use in other rifles, but the receiver must either have a 16" bbl installed, or registered as an SBR if the short bbl is retained. HK owners do this all the time, as the most common conversion was a trigger pack or sear. If they own one HK weapon, they get say their "MP5" clone married to the pack. Later, when they acquire several HK rifles they divorce and SBR the original so they can swap it out amongst their several rifles.

It is my understanding that it depends on the status the receiver. If you bought a new 10/22 receiver that had never had a stock on it and built it as a pistol then there would be no issue about the short barrel. There would be one stamp for the can and one stamp for the trigger pack (machine gun conversion device). With the pack in the pistol a stock can be added. A machine gun trumps SBR.

If the 10/22 receiver was registered as a machine gun before the '86 ban then there would still only be two stamps. One for the can and one for the registered receiver machine gun.

If the 10/22 had been a rifle (had a stock on it) before the barrel was shortened then that would depend on whether the can was "permanently attached to the barrel to bring the total barrel length beyond 16". If the can could be removed and you wanted the option of putting the trigger pack into another 10/22 then there would need to be three stamps. One for the can, one for the trigger pack and one to register the 10/22 as an SBR because the barrel was shorter than 16".

It is so easy to change a 10/22 barrel, I would put the $200 into another barrel that is over 16". Then switch the barrel when I want to switch the pack. You must have one 16"+ barrel per rifle receiver. Is that a convoluted enough answer for you?

I believe that the trigger pack must be married to the receiver on the paperwork for it not to be considered an SBR as well if the barrel or overall length requirements are not met by the host firearm.

If the reciever was never built into the gun before conversion, and it was built pre-86 as a MG with a dedicated suppressor (permanently attached to the barrel/receiver?) then it would be a one-stamp gun as well. But Ruger wasn't selling stripped receivers at the time,and there was no knock off recievers available so you will never find one. I believe my buddy's factory MP5SD is a one stamp gun. His registered receiver built from a HK94 SD is a two stamp gun.

A 10/22 bbl normally comes off with the removal of two screws, the suppressed bbl assembly would be considered a removeable suppressor and require a stamp of it's own. It doesn't matter if the receiver was ever a rifle before conversion, if the receiver is what was registered as the conversion then the receiver is and always will be an MG. If the trigger assembly or parts thererof were the registered part then that is the MG and whatever they are attached to would need an SBR stamp or be "married" to that conversion pack.

A "Factory" MP5SD would be an imported firearm and those are only allowed in as dealer samples since 1968. If it was imported prior to that it is a rare animal as the SD was first made in 1974. There would be no stamps as the dealer samples transfer tax-free. The factory suppressor is also removeable so it would need two registrations as well.

I own a Flemming HK sear. I originally purchased it in a Vollmer converted HK94. Vollmer installed a 8.85" Navy barrel (threaded muzzle with integral 3-lug), paddle mag release and remarked the HK94 to "MP5". The host was noted by serial # on the paperwork for the sear. That is being "married" together, since the barrel was less than 16". I have since filed a Form 1 and registered the 94 as a Short Barreled Rifle.

I now have several host firearms. All are pistols. With the sear installed, I can add a stock to the pistol. The stock can be added because the conversion device (sear) is installed in the pistol, making it a machine gun. To place the sear in another host, the stock must be removed, converting the host firearm back into a pistol.

To accurately answer "noobert"'s question we would need to know:

1. Was the receiver of the 10/22 registered as a machinegun prior to May 19, 1986, or is the 10/22 a machinegun because of installation of a conversion device for a 10/22 that was registered as a machinegun prior to May 19, 1986?

2.If a registered conversion device is used to convert the host 10/22 to a machinegun, was the host 10/22 a rifle or a pistol before installation of the conversion device?

3.Is the can permanently attached to the barrel?

Scott

Last edited by scottinthegrove; 02-13-2010 at 02:04 PM.
Reason: Clarity